By 2025, consumers in emerging markets will spend $30 trillion annually, which will be "the biggest growth opportunity in the history of capitalism," according to the report.
For centuries, the percentage of people in the world with discretionary income (consumers) was dramatically smaller than the percentage of people who had just about enough for necessities or less.
But since the industrial revolution, the percentage of consumers has been rising. And some of the biggest growth will happen between now and 2025 thanks to the emerging markets.
This chart that shows how much the consumer class will grow in developed and emerging markets:
